Aussie mining company strikes it rich with Angola's biggest-ever diamond

An Australian mining company's shares sky-rocketed by more than 30 percent today upon news it had discovered the largest diamond ever found in Angola.

Lucapa Diamond Company has not yet valued the 404-carat rock, thought to be the 27th biggest recorded diamond in history, but initial estimations suggest it is worth as much as $20 million.

The discovery continues a rich vein of good mining fortune for Lucapa, which has uncovered 60 large diamonds since work began on the site in Angola's Lunda Norte province, in the country's north-east, in August last year.

Lucapa is chaired by Perth mining veteran Miles Kennedy, who described the find as "spectacular".

"When we first looked at the property, 3,000 square kilometres of untouched ground, 700 kilometres inland from the coast, you are talking about a very, very remote area," Mr Kennedy told ABC.

"The results today are a wonderful vindication of eight years of pretty hard work."

Mr Kennedy said the cash injection would allow his company to expand operations in the area.